Question

The edge length of unit cell of a metal having molecular weight `75 g mol^(-1)` is `5 Å` which crystallizes in cubic lattice. If the density is `2 g cc^(-1)`, then find the radius of metal atom `(N_(A) = 6 xx 10^(23))`. Give the answer in pm.
A. 217pm
B. 210pm
C. 220pm
D. 205pm

Answer 1

Correct Answer - A
`rho=(ZA)/(NV)`
`Z=(rhoNV)/(A)=(2xx6xx10^(23)xx(5xx10^(-8))^(3))/(75)`
`n=2rArrr=sqrt(3)/(4)a=sqrt(3)/(4)xx5=2.165overset(@)A=216.5`pm